cluster_within_distance_garray()

Datum cluster_within_distance_garray

(

PG_FUNCTION_ARGS

)

Definition at line 2953 of file postgis/lwgeom_geos.c.

{
        Datum* result_array_data;
        ArrayType *array, *result;
        int is3d = 0;
        uint32 nelems, nclusters, i;
        LWGEOM** lw_inputs;
        LWGEOM** lw_results;
        double tolerance;
        int srid=SRID_UNKNOWN;
 
        /* Parameters used to construct a result array */
        int16 elmlen;
        bool elmbyval;
        char elmalign;
 
        /* Null array, null geometry (should be empty?) */
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();
 
        array = PG_GETARG_ARRAYTYPE_P(0);
 
        tolerance = PG_GETARG_FLOAT8(1);
        if (tolerance < 0)
        {
                lwpgerror("Tolerance must be a positive number.");
                PG_RETURN_NULL();
        }
 
        nelems = array_nelems_not_null(array);
 
        POSTGIS_DEBUGF(3, "cluster_within_distance_garray: number of non-null elements: %d", nelems);
 
        if ( nelems == 0 ) PG_RETURN_NULL();
 
    /* TODO short-circuit for one element? */
 
        /* Ok, we really need geos now ;) */
        initGEOS(lwpgnotice, lwgeom_geos_error);
 
        lw_inputs = ARRAY2LWGEOM(array, nelems, &is3d, &srid);
        if (!lw_inputs)
        {
                PG_RETURN_NULL();
        }
 
        if (cluster_within_distance(lw_inputs, nelems, tolerance, &lw_results, &nclusters) != LW_SUCCESS)
        {
                elog(ERROR, "cluster_within: Error performing clustering");
                PG_RETURN_NULL();
        }
        pfree(lw_inputs); /* don't need to destroy items because GeometryCollections have taken ownership */
 
        if (!lw_results) PG_RETURN_NULL();
 
        result_array_data = palloc(nclusters * sizeof(Datum));
        for (i=0; i<nclusters; ++i)
        {
                result_array_data[i] = PointerGetDatum(gserialized_from_lwgeom(lw_results[i], NULL));
                lwgeom_free(lw_results[i]);
        }
        pfree(lw_results);
 
        get_typlenbyvalalign(array->elemtype, &elmlen, &elmbyval, &elmalign);
        result =  construct_array(result_array_data, nclusters, array->elemtype, elmlen, elmbyval, elmalign);
 
        if (!result)
        {
                elog(ERROR, "clusterwithin: Error constructing return-array");
                PG_RETURN_NULL();
        }
 
        PG_RETURN_POINTER(result);
}

References ARRAY2LWGEOM(), array_nelems_not_null(), cluster_within_distance(), gserialized_from_lwgeom(), LW_SUCCESS, lwgeom_free(), lwgeom_geos_error(), and SRID_UNKNOWN.

Referenced by pgis_geometry_clusterwithin_finalfn().

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